Two of the major features of schizophrenia spectrum illness, negative and cognitive symptoms, have been associated with poor functional outcome and burden of illness. Given the proposed role of dopaminergic hypoactivity, augmentation with psychostimulants has been postulated as one of the potential treatment options for negative and/or cognitive symptoms of schizophrenia. The major drawback for use of these agents is a potential risk of relapse or worsening of psychosis through direct or indirect dopamine agonism activity and a great deal of caution has been called for use of stimulants in individuals with psychosis. However, preliminary results of earlier studies indicated improvement of negative and cognitive symptoms with off-label use of adjunctive psychostimulants. The present study aims to assess off-label use of adjunct psychostimulants in patients with schizophrenia in a tertiary mental health centre, focusing on efficacy and safety.

This project focuses on assessing efficacy of off-label use of adjunctive methylphenidate ER 36 mg among 24 stable patients with schizophrenia spectrum illness. This is a single centre study at the Royal Ottawa Mental Health Centre, Ottawa, Canada. An open-label fixed dose controlled cross-over trial is planned. Individuals (inpatients and outpatients) with schizophrenia who are stable on antipsychotic medications will be invited to participate in the study. Participants will be randomized into receiving four weeks of methylphenidate extended release (ER) 36 mg or treatment as usual and will switch group assignments for another 4 weeks. The duration of the study is 12 weeks for each participant, including 8 weeks of treatment (4 weeks treatment as usual and 4 weeks treatment as usual + adjunctive methylphenidate ER) and a follow-up visit at 12 weeks (study end point). A number of standardized scales will be used to measure functional capacity, cognition and symptom severity.

Inclusion Criteria:

• Adult between the ages of 18-55; we chose an upper age limit of 55 years to exclude patients with potential age-related cognitive impairments which usually occur about a decade earlier in patients with schizophrenia
• Inpatient or outpatient with schizophrenia spectrum illness, on any antipsychotic medication
• Clinically stable for the past 4 weeks
• Able to communicate in English

Exclusion Criteria:

• Have known sensitivity to methylphenidate ER, as documented in the electronic medical record OR, as reported by the patient AND verified by pharmacy

• Have had treatment with ECT in the past 6 months

• Have a history of traumatic brain injury

• Have a contraindication to psychostimulants including:

  1. Uncontrolled hypertension
  2. Significant cardiovascular abnormality including history of cardiac interventions, history of myocardial infarction, unstable arrhythmia, congenital heart disease
  3. Known family history of premature cardiac death (for males <45, females <55)
  4. Known history of glaucoma

• Are currently pregnant or planning to become pregnant- a rapid urine pregnancy test will be done for female participants, and a refusal to take the test or a positive test will exclude the participant

• Have a diagnosis of substance induced psychosis

• Have any of the following diagnoses: neurodevelopmental delay, intellectual disability or neurocognitive disorder (dementia)

• Have a diagnosis of another currently significant and unstable psychiatric condition (i.e. depressive episode, active substance use disorder, etc.)

• Have a history of previous safety concerns directly driven by positive symptoms (e.g history of suicide attempt as directed by auditory hallucinations)

• Have current active suicidality

An open-label fixed dose controlled cross-over trial is planned.